1. Field of the Invention
This invention relates to cluster bombs, and more particularly to a detonator control circuit for the individual bomblets carried within a cluster bomb.
2. Description of the Prior Art
Cluster bombs have been used for some time to provide area coverage from a single bomb drop. Up to several hundred bomblets are carried within a single outer housing or canister, which separates into two parts when dropped from an aircraft and releases the bomblets. The individual bomblets ideally fall in a predetermined dispersion pattern to cover a large area. Some cluster bombs have no facilities for communicating with individual bomblets, and the bomblets explode upon impact or after a built-in delay period. In a more sophisticated type of cluster bomb, each of the individual bomblets is connected to a central controller by means of a wire harness, with separate cables running from the harness to each individual bomblet. The use of such cables makes it possible to communicate with the bomblets after they have been positioned in the bomb canister, for purposes such as arming the bomblets or providing a common detonation delay time to each of the bomblets.
While the use of such wire harness connections provides greater versatility in the applications for which the cluster bomb may be used, it also limits the performance of the bomb. It is generally desirable that the bomblet dispersion pattern be homogeneous over a large area. The forces acting on the bomblets as they are released from the cluster bomb are critical in determining the dispersion pattern, with only a few ounces of force on each bomblet being sufficient to greatly distort the pattern. One probe with the prior art wire harness approach has been that, in order to provide communication with the bomblets, the wire harnesses have had their cables mechanically connected directly to each bomblet. When the bomblets are released, they must then be disconnected from their respective cables in order to fall freely. Various attempts have been made to disconnect the bomblets without adversely effecting their dispersion pattern, but none have been entirely successful.
In addition to the separation problems mentioned above, the wire harness approach is quite expensive, in large part because it requires a separate cable for each of typically several hundred bomblets. Furthermore, none of the prior art cluster bombs have a capability, after the bomblets have been packaged within the bomb canister, of programming each of the bomblets with individual detonation delay times. Such a capability would be desirable in order to have the bomblets detonate at predetermined time intervals over a large ground area, and thus deny the area to an opposing force for the period that the bomblets continue to detonate.
In a companion U.S. patent application by Edward V. LaBudde, Ser. No. 590,215, filed Mar. 16, 1984, now Pat. No. 4,724,766, and entitled "Cluster Bomb System and Method", a new type of cluster bomb is described in which each of the bomblets is provided with an individual programmable detonator control. A signal transmission means electromagnetically transmits program information signals to the vicinity of each bomblet, while an electromagnetic signal coupler within each bomblet provides an interface between the transmission means and the detonator control to program the detonator control in response to program information signals delivered by the transmission means. In the preferred embodiment the signal transmission means is an electrically conductive wire positioned adjacent to but mechanically detached from, each of the bomblets. The wire serves as a primary transformer winding, each bomblet being provided with a multi-turn secondary winding to receive signals from the wire. The wire preferably extends through an opening in each bomblet, with the secondary windings disposed around the periphery of the openings. In order to rapidly pull the wire away when the bomb canister opens without imparting any significant force to the bomblets, the wire is mechanically attached to the canister at selected locations, and the canister is adapted upon opening to sever the wire and pull it away from the bomblets.
The detonator control for each bomblet includes an address code storage means for storing an address code which is unique for that bomblet, thereby enabling each bomblet to be individually accessed from the transmission wire by the transmission of an appropriate address code. In the preferred embodiment the address codes for the various bomblets are arranged in sequence. Means are provided to access the address codes stored in each bomblet in response to an actuating signal from the transmission wire, such that the bomblets sequentially detect a predetermined address code in response to successive actuating signals. In this manner the bomblets can be individually accessed in sequence by the repeated transmission of a single address code.
The detonator control for each bomblet further includes a timer which activates the bomblet's detonating mechanism after a delay period established by the timer. The timer is connected to receive a timing delay signal from the transmission wire when its respective bomblet is addressed. Each of the bomblets is programmed with an individual detonation time delay by repeatedly transmitting a predetermined address code, adjusting the address code stored in each bomblet with each transmission so that a different bomblet is accessed with each transmission, and alternating the address code transmissions with desired time delay program signals. In this manner, each bomblet in turn is accessed and programmed with an individual detonation time delay. Each bomblet also includes a mechanism which is responsive to the bomblet being released from the bomb canister for actuating the detonator timer to begin a detonation timing cycle, as determined by the delay programmed into the particular bomblet.
The LaBudde patent application also describes the use of an initiation signal to initially clear the timer and establish an initial address count for each bomblet. The initiating, address count and time delay program signals are in the form of pulses of varying width, and each bomblet is provided with pulse width discrimination circuitry for distinguishing between the various signals.